Cooled Radiofrequency Ablation for Pain Relief After Total Knee Replacement

PainRelief.com Interview with:

Felix Gonzalez, M.D.
Assistant professor, Division of Musculoskeletal Imaging
Department of Radiology and Imaging Scienc
Emory University School of Medicine
Atlanta, Georgia

Dr. Gonzalez

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: Total knee arthroplasty is a common procedure performed worldwide for the treatment of symptomatic knee arthritis. Unfortunately, approximately 20% of those patients develop chronic pain after the surgical intervention in the setting of no complications such as infection or hardware loosening. The reason for this is not known at this point although theories exist.

The new study focused on 21 patients who were experiencing persistent chronic pain after total knee replacement, without underlying hardware complications. The patients had all failed conservative care. They filled out clinically validated questionnaires to assess pain severity, stiffness, functional activities of daily living and use of pain medication before and after the procedure. Follow-up outcome scores were collected up to one year after the C-RFA procedure.

In the end, the study found, patients with knee arthritis reported an 70% drop in their pain ratings approximately, on average.


PainRelief.com: What should readers take away from your report?

Response: The procedure is a form of radiofrequency ablation, where doctors use needles to send a low-grade electrical current to nerves that are transmitting pain signals from the arthritic joint to the brain. The current heats and damages the nerve fibers, rendering them unable to deliver those pain messages.  In the United States, a number of ablation devices are cleared for treating low back pain and knee osteoarthritis. 


Radiofrequency ablation electrode is placed into the introducer needle after the placement of the introducer needle



At this point, the procedure is slowly becoming a more established treatment, said Dr. Felix Gonzalez, a radiologist at Emory University School of Medicine in Atlanta. Gonzalez called the results “promising” and said, in his experience, there have been no major complications from the procedure, such as bleeding or infections — though those are potential risks.  And before the ablation is done, Gonzalez explained, patients go through what is basically a trial run. They are given an injection of numbing medication near the nerves believed to be generating the pain signals. If the pain abates, that means targeting the same nerves with ablation will likely work, too — longer term. 






PainRelief.com: What recommendations do you have for future research as a result of this work?

Response: Larger scale studies need to be performed to decipher the full applications of this novel technique. 

Any disclosures? I am a consultant for Avanos Medical. 

Citation: RSNA 2021

Utilization of Cooled Radiofrequency Ablation for the Treatment of Uncomplicated Total Knee Arthroplasty Chronic Pain and Stiffness: Initial Single Institution Pilot Study

[Co-authors are Janice M. Newsome, M.D., Nima Kokabi, M.D., Zachary Bercu, M.D., Mircea Cristescu, M.D., M.B.A., Adam Singer, M.D., Philip Wong, M.D., Mohammed Loya, M.D., Fiza Khan, D.O., and Andrew Tran.

Radiological Society of North America (RSNA) 
Nov 23, 2021, 05:00 ET

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Study Compares PRP to Placebo For Pain Relief in Knee Arthritis

PainRelief.com Interview with:

Professor Kim Bennell FAHM
Barry Distinguished Professor | NHMRC Leadership Fellow
Dame Kate Campbell Fellow
Centre for Health Exercise and Sports Medicine
Department of Physiotherapy
Melbourne School of Health Sciences
The University of Melbourne, Victoria Australia

Prof. Bennell

PainRelief.com:  What is the background for this study?

Response: Osteoarthritis is a common chronic painful joint condition with no cure that often leads to costly joint replacement surgery. Treatments are needed that can not only reduce symptoms but also slow structural progression of the disease in order to reduce the burden of knee OA.  There are no approved disease-modifying treatments available at present. 

Platelet-rich plasma (PRP) injections have become a widely used treatment for knee osteoarthritis (OA) in recent years despite the fact that the evidence to support their effects is limited and not of high quality. For this reason, clinical guidelines currently do not recommend PRP for the management of knee osteoarthritis.

To address this gap in knowledge, our study aimed to compare the effectiveness of PRP injections to reduce knee pain and slow loss of medial tibial cartilage volume over a 12-month period. We did this by conducting a clinical trial of 288 people with mild to moderate knee OA. The study included a placebo group where participants were injected with saline into the knee. Participants and the injecting doctors were blind as to whether PRP or saline was injected into the knee.

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Case Report Describes Pain Relief from Chronic Migraines with LIFE Diet

PainRelief.com Interview with:
David M. Dunaief, M.D.

Principal Investigator
MedicalCompassMD.com

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: As an internist focusing on dietary intervention, I have been caring for patients with chronic diseases for the past 12 years. Many of my patients have had rapid, marked improvements when they adhere to my LIFE (Low Inflammatory Foods Everyday) diet. The diet, as well as objective evidence that it reduces systemic inflammation (lowers serum C-reactive protein levels), has been described in the peer-reviewed publications:

https://journals.sagepub.com/doi/full/10.1177/1559827619894954 

and https://journals.sagepub.com/doi/full/10.1177/1559827620962458.

In addition to improving migraines, the diet has improved symptoms and blood chemistries in patients with high blood pressure, high cholesterol, diabetes, cancer, auto-immune diseases, inflammatory bowel disease, and others. In this case report, we describe a patient who suffered from debilitating migraines for 12.5 years, and who had minimal benefit from avoiding dietary triggers or medications. Within 3 months of adopting the LIFE diet, he was migraine free and remained that way for 7.5 years.

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Less-is-More Approach to Pain Relief After Surgery

PainRelief.com Interview with:
Dr Deanne Jenkin PhD
UNSW Australia,
now Research Fellow at The Daffodil Centre
Sydney, Australia

Dr Jenkin

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: At the time, long-term opioid use for chronic non-cancer pain was increasing and there were signs that their benefit was overestimated whilst the harms were underestimated. Our randomized trial found that after going home from fracture surgery, strong opioids were not better for pain relief compared to a milder, potentially safer opioid alternative.

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Study Finds Physical Exercise Increases Body’s Own Cannabis-Type Substances

PainRelief.com Interview with:
Amrita Vijay PhD
Division of Rheumatology
Orthopedics and Dermatology
School of Medicine
University of Nottingham
Nottingham, UK

Dr. Vijay

PainRelief.com:  What is the background for this study? What are the main findings?

Response: We carried out this research as we wanted to see if exercise had an effect on the levels of anti-inflammatory substances produced by gut microbes and on endocannabinoids (i.e cannabis-like substances) produced by our bodies.  

One of the key findings of the study is that physical exercise increases levels of the body’s own cannabis-type substances and highlights a key link between how substances produced by our gut microbes interact with these cannabis-like substances and reduces inflammation.  

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Study Identifies New Compound That Alleviates Chronic Pain in Preclinical Models

PainRelief.com Interview with:
Rajesh Khanna, PhD
Professor and Vice Chair of Research, Department of Pharmacology,
Associate Director of Research, Comprehensive Pain and Addiction Center
University of Arizona 

Dr. Rajesh Khanna,

Starting January 2022:
Professor, Department of Molecular Pathobiology
Director, NYU Pain Center
College of Dentistry New York University

PainRelief.com:  What is the background for this study? 

Response: Chronic pain conditions cause an immense burden on society due to their astonishingly high prevalence and lack of effective treatments. The National Institutes of Health estimates that nearly 100 million people in the United States suffer from chronic pain. Nearly 20-30% of patients prescribed opioids for chronic pain misuse them, according to the National Institute on Drug Abuse.  In 2019, nearly 50,000 people in the U.S. died from opioid-involved overdoses and that number increased to nearly 70,000 in 2020. There is clearly an urgent need for non-addictive treatments for chronic pain.

The voltage-gated sodium channel NaV1.7 is preferentially expressed in the peripheral nervous system within ganglia associated with nociceptive pain. This channel modulates the threshold required to fire action potentials in response to stimuli and has been established as a key contributor to chronic pain. Chronic pain states can result from upregulated NaV1.7 expression which has been shown to occur in association with diabetic neuropathy, inflammation, sciatic nerve compression, lumbar disc herniation, and after spared nerve injury. The exact pathways leading to the dysregulation of NaV1.7 are poorly understood, but likely involve mechanisms related to its surface trafficking and regulation via protein-protein interactions.

Our previous work identified the collapsin response mediator protein 2 (CRMP2) as a novel regulator of NaV1.7 function and uncovered the logical coding of CRMP2’s regulatory functions. We found that if CRMP2 is phosphorylated by cyclin dependent kinase 5 at serine 522 and also modified by SUMOylation at lysine 374 by the SUMO conjugating enzyme Ubc9, then NaV1.7 is functional. When not SUMOylated, CRMP2 recruits the endocytic proteins Numb, Nedd4-2, and Eps15, triggering clathrin mediated endocytosis and internalization of NaV1.7. When not at the cell-surface, sodium currents are reduced, alleviating NaV1.7-associated chronic pain. This action of CRMP2 is highly selective for NaV1.7, as no effects on other voltage-gated sodium channel subtypes are observed.

Previous efforts to target NaV1.7 for pain relief have focused on development of direct channel blockers, but this approach has been unsuccessful. Disclosed reasons for failure of these NaV1.7-targeting drugs include issues with:
(a) central nervous system penetration,
(b) lack of selectivity (e.g., of Biogen’s Vixotrigine),
(c) inadequacy of pain models, and
(d) insufficient channel blockade.

These factors culminate in continued action potential firing and failure to relieve pain, which has led to skepticism regarding targeting of NaV1.7.

We hypothesized that targeting CRMP2 with a small molecule to prevent it’s SUMOylation would be a novel and effective approach to indirectly regulating NaV1.7 for the treatment of chronic neuropathic pain.

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Physical Therapy After Knee Replacement Linked to Less Long Term Opioids for Pain Relief

PainRelief.com Interview with:
Deepak Kumar, PT, PhD
Assistant Professor, Physical Therapy
Assistant Professor, BU School of Medicine
Director, Movement & Applied Imaging Lab

Dr. Kumar

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: We investigated the association of physical therapy interventions with long-term opioid use in people who undergo total knee replacement surgery.   For people with advanced osteoarthritis, total knee replacement is the only option. The number of total knee replacement surgeries has been increasing and is expected to rise exponentially over the next few years with an aging population and rising rates of obesity. However, up to a third of patients continue to experience knee pain after this surgery. Also, a significant proportion of people become long-term opioid users after total knee replacement. Reliance on opioids may reflect a failure of pain management in these patients. Given that physical therapy interventions are known to be effective at managing pain due to knee osteoarthritis, we wanted to study whether physical therapy before or after surgery may reduce the likelihood of long-term opioid use.

We used real-world data from insurance claims for this study. In our cohort of about 67,000 patients who underwent knee replacement between 2001-2016, we observed that, receiving physical therapy within 90 days before surgery or outpatient physical therapy within 90 days after surgery were both related to lower likelihood of long-term opioid use later. We also observed that initiating outpatient physical therapy within 30 days and 6 or more sessions of physical therapy were associated with reduced likelihood of long-term opioid use compared to later initiation or fewer PT sessions, respectively. However, we did not see an association between type of physical therapy. i.e., active (e.g., exercsise) vs. passive (e.g., TENS) and long-term opioid use.

Importantly, most of our findings were consistent for people who had or had not used opioids previously. We also were able to account of a larger number of potential factors that could confound these associations because of the large sample size. However, there are limitations to our work. Since we only had access to insurance claims data but not to health records, we are unable to make any inferences about association of physical therapy with pain or quality of life, etc.

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UCI Scientists Discover Pathway Blocking Transition from Acute to Chronic Pain

PainRelief.com Interview with:

Daniele Piomelli PhD Distinguished Professor, Anatomy & Neurobiology Louise Turner Arnold Chair in Neurosciences Joint Appointment, Biological Chemistry and Pharmacology School of Medicine Director, Center for the Study of Cannabis University of California, Irvine
Dr. Piomelli

Daniele Piomelli PhD
Distinguished Professor, Anatomy & Neurobiology
Louise Turner Arnold Chair in Neurosciences
Joint Appointment, Biological Chemistry and Pharmacology
School of Medicine
Director, Center for the Study of Cannabis
University of California, Irvine

PainRelief.com: What is the background for this study?

Response: The pain caused by physical trauma or by surgery can disappear in a relatively short time — or linger for months or even years. In some cases, for example after open heart surgery, the percent of people who develop persistent pain can be as high as 40%. Breast and knee surgery, among others, have similar outcomes. We still don’t understand how acute pain after an injury becomes chronic.  

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Brainstem’s Role in Placebo and Pain Perception Highlighted

PainRelief.com Interview with:
Lewis Crawford, B.Sci (Hons), PhD Candidate 
Neural Imaging Laboratory | Faculty of Medicine and Health
University of Sydney 

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: This study was performed as a means to accurately and robustly define the areas of the brainstem responsible for alleviating and enhancing pain via conditioning and expectation alone, that is, the phenomena of placebo analgesia and nocebo hyperalgesia. The reason we were able to do this was by being able to access a 7-tesla ultra-high field MRI, one of only two in Australia, that allowed us to resolve the small nuclei in the brainstem which make up descending analgesic circuitry (they carry signals from your brain to your spinal cord).

We found that a central pathway, comprised of the midbrain Periaqueductal Gray (PAG) and Rostral Ventromedial Medulla (RVM), acted during both phenomena, however in opposite ways. We also identified several other nuclei as playing a role in the modulation of pain which, prior to this study, had not been explored or suggested to play a role in this context. We believe that the brainstem circuitry we defined here enables further research into mechanisms responsible for analgesia and hyperalgesia and will promote further investigation into brainstem function in humans. 

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Astronauts Risk Herniated Discs and Back Pain From Space Flight

PainRelief.com Interview with:
Dr. Radostin Penchev
Johns Hopkins Medicine

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: Although fewer than 600 people have travelled to space, human space travel is expected to exponentially surge with several companies now offering space excursions as well as with the establishment of the U.S. Space Force in 2019. In parallel with this effort, NASA plans to have a sustained presence on the Moon by 2028.

It turns out that more than 50% of astronauts experience back pain (termed space adaptation back pain) during their mission and are over 4 times more likely to suffer from herniated discs than the normal population. As such, physicians should anticipate a surge in space-related back pathology. More importantly, understanding the cause of back pain in astronauts may also improve the care for other austere environment populations including deep sea divers, fighter pilots and high-altitude explorers.

In this comprehensive review of the literature, we examined the epidemiology, potential causes, and treatments for spinal pain in astronauts.

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